Electric discharge device



June 24, 1958 D. E. MARSHALL ELECTRIC DISCHARGE DEVICE Filed Feb. 26, 1954 Fig.l.

INVENTOR Donald E. Marshall.

Fig.3.

BY 4% ATTORNEY United States Patent ()fiiice 2,840,737 ELECTRIC DISCHARGE DEVICE Donald'E. Marshall, Montour Falls,'N. Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., .a corporation of Pennsylvania Application February 26, 1954, Serial No. 412,868 7: Claims. (Cl.313-13) My invention relates, in general, toelectric discharge devices, and, more particularly, .to those devices cooled by the circulation of a cooling medium between the en velopeor wall of the device and a cooling jacket.

It is an object of my. invention to provide an improved control system for an electrical device which is cooled by the flow ofa cooling medium.

It is another object to provide a protective device for an electrical discharge device which is cooled by the flow of a cooling medium for protecting the electrical discharge device from overheating.

l t is another object to provide an improved system for controlling the cooling medium for an electrical discharge device of the type having a cooling jacket around an inner casing or envelope for elements .of the electrical discharge device.

It is another object to provide an improved electrical discharge device' characterized in having a cooling jacket surrounding a substantial portion of the electrical discharge'envelope with means for determining the temperature of'the electrical discharge envelope on the exterior surface of the cooling jacket.

It is another object to provide an electrical discharge device having an inner and outer casing provided with means for sensing the temperature of the inner casingon the external "surface'of the outer casing.

' Itis another object to provide an improved electrical discharge'device having an inner andouter casing which has an elemental area on the outer casing representative of the temperature of the innercasing.

These and other objects are effected by my invention, as will be apparent from the'following description, taken in accordance with the 'acco panying drawingthroughout which like reference characters indicate like parts, and in which:

Figure lis a cross sectional view of anelectrical discharge device embodying my invention;

"Fig. '2 is a partial cross-sectional view of a modification;

Fig. 3 is a partial cross=sectional view of another modification; and

Fig. 4 is a partial cross-sectional view of still another modification.

Referring in detail to Fig. 1,I have shown my inventionapplied to a gaseous electrical discharge device. vThe electrical discharge device comprises an inner tubular member or casing-11 of suitablematerial, such asstainlesssteel. The casing 11 is closed at the lower endby a plate member 13 having a downward turned flange 15 around the periphery of the plate'13. ,The downward turne'd 'flange '15 is welded to thelower portion of the casing *11 'Thelower end of the casingll below the downwardturned flange '15 of the plate memberJS is fiaredoutabout its periphery. Thisfiared portion. 14 is welded to an outer tubular casing 17.-at.substantially* the lower edges of the inner casin .11 and the .outer casingi'1 7.

2,840,737 Patented June 24, 1958 The upper portion of the inner casing 11 also has a flared out portion 12 and the external surface thereof is fitted against the inner surface of the upper portion of the outer casing 17. The upper edges of the inner casingv 11 and the outer casing 17 are then welded together. An annular space 19 is thereby provided between the two tubular members 11 and 17.

An opening 21 is provided in the tubular member 17 near the lower portion of the space 19 so as to permit the introduction of a cooling medium, such as water, or the like, between the casing 17 and 11. Another 0pening 23 is provided near the upper portion of the space 19 in the tubular member 17 so as to provide an outlet for the cooling medium introduced into the space 19. In this manner, a cooling medium may be introduced into the space 19 and be circulated throughout the space 19 from a source of cooling medium (notshown) for the purpose of reducing the temperature of the inner casing 11.

An outwardly formed protuberance or dimple portion 25 is provided on the inner casing 11 which forms a wall of the space 19 so as to make intimate contact with the outer cylinder 17. at the point or elemental area 27. The dimple 25 should be located substantially at a point on the inner wall 11 near the elementswithin the casing 11 which operate at. the highest temperature, or whose temperature changes most rapidly with change in tube loading or rate of flow of the cooling medium.

The method or device for obtainingintimate contact between the inner and outer wall may have many variations and may take the form of an inward dimple on the outer wall 17 which is in intimate contact with the inner wall as shown in Fig. 2, or may take the form of a block or element of heat-conducting material 61 inserted into the space 19 atthe desired position as shown in'Fig. 3. The material 61 is in intimate contact with the inner wall 11 and the outer wall.17.

The scope of my invention is not intended to be limited in any respect to the forms that I have suggested. It is the intent of my invention to provide means for obtaining an area on the external surface of the outer wall which is representative of the temperature of the inner Wall by a simple and economical means.

The plate member 13 which serves as a closure member for the bottom portion of the inner tubular member 11 also provides a location for a pool cathode 29 of a material such as mercury. The pool cathode 29 is thereby retained in the lower portion of the envelope formed by the plate 13 and the adjacent walls of the envelope or casing 11. A terminal and supporting member 9 is welded or brazed to the plate 13.

A pointed make-alive or igniting device 31 having a tapered point is'inserted'into' the mercury pool cathode 29 in a suitable manner. The igniting device 31 is of a high resistance material such as boron carbide material. The igniting device 31 is supported by the arm 33 which is, in turn, supported by a rod 35 passing through the plate 13 and insulated from the mercury pool cathode 29 and plate 13 by suitable means 37. A terminal 38 is provided for the igniting device 31 on the exterior portion of the device. A suitable evacuating or pinch-oil tube (not shown) is provided for the evacuation of the internal volume within the inner envelope 11.

An anode 16 of a suitable material, such as graphite, is positioned in the upper envelope formed by the casing 11. The anode 16 is provided with a supporting conductive rod 13 which extends above the upper portions of the casing 11 and 17 so as to provide an external terminal 20 for the anode 16. A plate or disc member 22 is pro vided having a downward turned flange 24 around its periphery in the center thereof for insertion over the anode rod 20. The aperture 26 of the disc 22which may also have an edge thereon'whi'ch is in the form of a flange is welded or brazed to the anode rod The plate member 22 is of any suitable material such as Kovar. The annular edge of the downward turned flange 24 on the plate 22 is sealed to the upper edge of a cylindrical member 28 of suitable material, such as borosilicate glass. The other or lower edge of the glass cylinder 28 is sealed to the inner flange 32 of an annular trough shaped member 30. The'surface of the outer flange 34 of the member is welded or brazed to the inner surface of the casing 11 below the flared out portion 12. The inner flange 32 of the member 30 is of a suitable material such as Kovar, while the remainder of the member 30 may be of mild steel. The inner flange 32 is resistance welded to the remainder of the member 30.

A thermostat of any suitable type is positioned on or near the external surface of'the casing 17 at the point or area 27.. Since the temperature of the point or area 27 is substantially the temperature of the inner wall or casing 11, the thermostat is responsive to the temperature of the inner wall 11.

In the specific embodiment shown in Fig. l, a heat conductive element 40 is attached to the wall or jacket 17 at thepoint 27. The element 40 is welded or brazed to the wall 17 or may be attached or retained against the wall 17 by any suitable means. A disc type thermostat 41, shown in this specific embodiment, is fastened to the conductive element by suitable means, such as the screw 42. The disc 41 is comprised of two disc layers 43 and 44 having difierent coefficients of heat expansion. Positioned on the periphery of the disc layer 44 and secured thereto are two contact elements 45 and 46 which are insulated from the layer 44 by respective insulatingmembers 47 and 48. A conductive element 51 is connected between the contacts 45 and 46 to provide an electrical connection.

A stationary contact 52 is provided for the contact 45, and a similar stationary contact 53 is also provided for the contact 46. Terminals 54 and 55 are provided on the respective contacts 52 and 53 for purposes of providing means of connecting the contacts of the thermostat element to any desired control circuit.

A cup-shaped member 57 may enclose the thermostat. The member 57 may also be utilized to affix the thermostat including the conductive element 40 against the jacket 17.

Referring to Fig. 2, the tube shown in Fig. l is modified in that a dimple 62 is placed in the outer wall. The dimple or deformation 62 is inward so as to be in intimate contact with the inner wall 11. The thermostat and mounting is also modified in Fig. 2 from that shown in Fig. l.

The disc 63 again is comprised of two layers 64 and 65 of conductive materials having different coefficients of heat expansion. Contacts 66 and 67 are secured directly to the periphery of the layer 65. The disc 63 is mounted to an insulating member 68 by means of a screw 69 with a spacer 70 provided between the disc 63 and the member 68. Contact members 71 and 72 are provided on the member 68 for the respective contacts 65 and 66. Terminals 73 and 74 are provided on the opposite sides of the member 68 for the respective contacts 71 and 72. The deformation 62 is of suflicient size so that the disc 63 may be inserted therein and the member 68 is of sufiicient size to cover the deformation 62. The member 68 is attached to the wall 17 so as to cover the depression formed by the deformation 62.

In Fig. 3. there is shown another modification of the device shown in Fig. l in that the dimple 25 is not provided in the inner wall. In place of the dimple 25, a heat conductive element 61 is positioned between the inner casing 11 and the outer casing 17 and in intimate contact therewith to provide the area 27. A similar thermostat may be used as previously described with reference to Fig. 1.

Referring in detail to Fig. 4, I have shown another possible mounting of a'the'rmo'st'aticdevice'oritlfe jaeket 17 of the tube. The method of transmittal of heat between inner envelope 11 and the jacket 17 may be of the type set out in Figs. 1, 2 or 3. A heat conductive member is brazed or soldered over the hot area 27 and extending over the hot spot area 27 to connect with adjacent areas which are in contact with the cooling medium. In this manner the heat conductive member 80 is not only heated by embossed inner cylinder but is cooled by the adjacent water cooled area. By enlarging the area of contact of the heat conductive member 80, it is found that the device is more responsive to the flow of the cooling medium.

In the device shown in Fig. 4, the thermostatic member and contacts are contained within the body 82. By merely fastening the members 80 and 82 together by any suitable means, such as the bolt 83, the thermostatic device is attached to the water jacket. This points out another advantage in that by an inexpensive modification, all tubes are adapted for the dismountable mounting of a thermostatic device. By this means the user is provided with one type tubethat is easily adapted to use with a thermostatic control. If the tube breaks down, the thermostatic control can be removed from the faulty tube and used on a replacement tube.

In operation, when the electrical discharge device shown in Fig. 1 has been rendered conductive in a suitable manner, a flow of current between the mercury cathode 29 and the anode 16 is obtained. The flow of current between the cathode 29 and the anode 16 results in the evolution of heat which in turn causes the temperature of the inner wall 11 to rise. The area 27 on the outer wall or jacket 17 will also rise in temperature and be at substantially the same temperature as the inner wall 11 due to the intimate contact. The heat due to the temperature rise on the area 27 is conducted by the heat conductive element 40 to the disc 41. This in effect allows the thermostat to operate or measure the temperature of the inner wall 11.-

The heat applied to the disc 41 causes the bimetallic discs 43 and 44 to bend outward around their periphery and if the rise of temperature is sufficient to cause the contacts 45 and 46 to make contact with the respective contacts 52 and 53, by the connection of suitable control circuits to the terminals 54 and 55, the, operation of the thermostat in closing the contacts 45 and 52; 46 and 53 may be used to operate the control circuit.

After the temperature is reduced, the thermostat will open the contacts which will, in turn, also open the control circuit.

The operation of the thermostat contacts may be used to regulate or control the flow of cooling medium through the space 19, the application or removal of voltages from the electrical discharge device or any other unit or combination of units.

From the foregoing description, it is seen that I have provided an improved electrical discharge device in which a cooling jacket is utilized with means for measuring the temperature of the inner wall on the external surface of the cooling jacket.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications without departing from the spirit and scope thereof.

I claim as my invention:

1. An electrical discharge device comprising an inner wall and an outer wall with a space between said walls adapted to conduct a cooling medium, said inner wall having an outwardly depressed dimple in intimate contact with said outer wall to provide an elemental area on the exterior surface of said outer wall representative of temperature of said inner wall, means for connecting a source of cooling medium to said space for oooling'a portion of said device, a thermal conductive member positioned in intimate thermal contact with said elemental area and a portion of the surrounding area on the exterior surface of said outer wall, and a heat responsive element positioned on said thermal conductive member for variably restricting flow of said cooling medium through said space to maintain the temperature of said inner wall at substantially a predetermined value.

2. A discharge device comprising an inner metallic envelope having therein at least a cathode and an anode, an outer metallic envelope substantially enclosing said inner envelope with a space between said inner and outer envelope for a cooling medium, an integral portion of said inner envelope extending outwardly so as to be in intimate contact with said outer envelope so as to provide an elemental area on the surface of said outer envelope representative of the temperature of said inner envelope, a thermal conductive member positioned on the exterior surface of said outer envelope and in intimate thermal contact with said elemental area and a portion of the surrounding area and a thermal responsive means positioned on said thermal conductive member for controlling the operation of said electric discharge device.

3. A discharge device comprising an inner metal casing having therein at least a cathode and an anode, an outer metal casing substantially enclosing said inner casing with a space between said inner and outer casing for a cooling medium, an integral portion of said inner casing extending outwardly so as to be in intimate contact with said outer casing so as to provide a thermal spot on surface of said outer casing representative of temperature of said inner casing, a thermal conductive member positioned on the exterior surface of said outer casing and in intimate thermal contact with said thermal spot and a portion of the surrounding area and a thermal responsive means mounted on said thermal conductive member for controlling the flow of said cooling medium through said space so as to maintain the temperature at a predetermined value.

4. An electrical discharge device comprising a metal envelope having therein at least a cathode and an anode, a metal jacket substantially enclosing said envelope with a space between said envelope and jacket for a cooling medium and integral portions of said envelope extending outwardly so as to be in intimate contact with said jacket so as to provide an elemental area on surface of said jacket representative of the temperature of said envelope and thermal responsive means positioned on said elemental area and a portion of the surrounding area of the exterior surface of said jacket for controlling circuit interrupting means for protecting said discharge device in response to overheating of said inner wall.

5. An electrical discharge device comprising a first envelope having therein at least a cathode and an anode, a second envelope enclosing said first envelope with a space between for the introduction of a cooling medium, a first heat conductor means positioned within said space and in intimate contact with said first and second envelope so as to provide an elemental area on the surface of said second envelope representative of the temperature of said first envelope, a second heat conductive means positioned in intimate contact with said elemental area and a portion of the surrounding area on the exterior surface of said second envelope and a heat responsive device mounted on said second heat conductive means.

6. An electrical discharge device comprising a metal envelope having therein at least a cathode and an anode, a metal jacket substantially enclosing said envelope with a space between said envelope and jacket for a cooling medium with integral portions of said jacket extending inwardly so as to be in intimate contact with said envelope so as to provide an elemental area on the surface of said jacket representative of the temperature of said envelope, a thermal conductive member positioned in intimate thermal contact with said elemental area and a portion of the surrounding area on the exterior surface of said jacket and a thermal responsive means positioned on said thermal conductive member for controlling circuit interrupting means for protecting said discharge de vice in response to overheating of said envelope.

7. An electric discharge device comprising an inner metallic envelope having therein at least a cathode and an anode, a second outer metallic outer envelope substantially enclosing said inner envelope with a space provided between said inner and outer envelope for a cooling medium, an integral portion of said inner envelope extending outwardly so as to be in intimate thermal contact with the surface of said outer envelope to provide an elemental area on the surface of said outer envelope representative of the temperature of said inner envelope, a thermal conductive member positioned in intimate thermal contact with said elemental area and a portion of the surrounding area on the exterior surface of said outer envelope, and a heat responsive device mounted on said thermal conductive member and in thermal contact therewith.

References Cited in the file of this patent UNITED STATES PATENTS 2,171,930 Gerecke Sept. 5, 1939 2,192,047 Miles Feb. 27, 1940 2,519,267 Marcum Aug. 15, 1950 2,530,935 Bock Nov. 21, 1950 2,612,613 Steiner Sept. 30, 1952 

